I've searched through many posts on this but can't really find the answer I'm looking for. I have a 2001 Grand Caravan with just over 120K miles. A few years ago I replaced the power steering reservoir due to the noisy cold startups and clogged screen. That noise has never come back but now I'm experiencing something different.

After extended driving, the power steering "groans" loudly. Once she sits and cools down it's back to normal. Would this also be due to the screen not allowing enough fluid through as it heats up and gets bubbly?

 

What did you refill system with? ATF 4 is now recommended in some dodge vehicles instead of power steering fluid.

 

Same thing here, 02 grand caravan, similar mileage. Groaning noise when the PS warms up. I have been told that thats the pump telling you its about to go out. We'll run it until it stops working. It is filled with PS fluid, weird that they would change to ATF4, I might try it out.

 

Yep, put ATF +4 in it when i changed the reservior.